Reducing Harmful Algal Blooms

The growth of algae that releases toxins are, in general, referred to as harmful algal blooms. A recent incident in Toledo, Ohio has highlighted the issue of over enrichment of water sources due to nutrients. Nearly half a million people in northwestern Ohio were without drinking water early in August 2014, after toxins produced by algae were found in the water supply.

The mayor of Toledo had been forced to ban city drinking water due to above-normal levels of toxins called microcystins produced by a type of blue-green algae. Algae occurs naturally in Lake Erie and most is harmless. But when toxins are released, they can exist for weeks or even months, according to the U.S. Environmental Protection Agency. Microcystins are not regulated by the EPA. In Ohio's case, the algae thrives on an overabundance of phosphorous. The main sources of this chemical include fertilizers, failing septic tanks and power plant emissions, according to the Ohio Environmental Protection Agency.

In particular, fertilizer has contributed to increased levels of dissolved phosphorous in Ohio's rivers, say Laura Johnson, a research scientist at the National Center for Water Quality Research at Heidelberg University in Tiffin, Ohio. Changing agricultural practices have led to the higher phosphorous levels. Since the mid-1990s, farms got bigger and started to apply fertilizer in a manner which does not get the fertilizer very deep into the soil, according to Johnson. Farmers also turned to no-till farming to control erosion, but the trade-off was increased run-off from the fertilizer, she said. UNEP, through the Global Partnership on Nutrient Management (GPNM) has been supporting efforts to look at how food security may be achieved and how the current low use efficiency of phosphorus may be increased by improved utilization strategies and the development of new technologies.

Harmful algal blooms have been reported in every U.S. coastal state, according to the National Oceanic and Atmospheric Administration. The toxic algal bloom that poisoned Ohio’s water is not just Ohio’s problem. The EPA defines these blooms as a “major environmental problem” in all 50 states. The last EPA National Lakes Assessment noted that out of more than 123,000 lakes greater than 10 acres in size spread across the U.S., at least one-third may contain the toxic algae. And consuming microcystis can be deadly — it has been known to kill dogs and livestock, and can cause abnormal liver function, diarrhea, vomiting, and other symptoms in humans.  In western Lake Erie, NOAA predicted "significant" blooms this summer. The harmful algal blooms were common in Lake Erie between the 1960s and 1980s, but after a 20-year hiatus, the blooms have been increasing over the past decade, according to NOAA.

Aside from Lake Erie, there are five other major U.S. water systems that are currently at risk from toxic algae blooms. These include Lake Okeechobee, in Florida; Klamath River, California; Jordan Lake, North Carolina; Cheney Reservoir, Kansas; and Sodus Bay, New York.

Phosphorus is essential, and human life is inextricably linked to the use of considerable amounts of P, particularly for food production. The GPNM concerns itself with critical issues related to sustainable phosphorus management, such as phosphorus-related pollution, the innovation potential of phosphate fertilizers and fertilizer production, uneven geographical distribution of phosphate resources, transparency of reserves, economic scarcity, and price volatility of phosphate products. The GPA, in order to fulfill its mandate, needs to identify the deficiencies in the world’s phosphorus flows, which is essential to understanding the issues of pollution, as well as supply security, losses, sinks and efficiency of phosphorus use, and the challenges to closing the phosphorus cycle, e.g. by recycling and other means.

Sustainable phosphorus management is a very complex issue that requires a global transdisciplinary process to arrive at a consensus solution. To gain a complete picture of the current phosphorus cycle, one requires knowledge from a broad spectrum of sciences, ranging from geology, mining, and chemical engineering; soil and plant sciences; and all facets of agricultural and environmental sciences to economics, policy, and behavioral and decision science. In order to identify options, drivers, and barriers to improving phosphorus flows, one requires capacity building initiatives and consensus building on the phosphorus use practices that must be changed and maintained, along with recognition of how changes in phosphorus use in the current market may be framed. Key actions to improving phosphorus management, improving nutrient use efficiency (NUE) and thereby improving food and energy production, while reducing P (& N) losses include:
  • Improving NUE in crop production, animal production, fertilizer and food supply
  • Reducing waste from phosphorus processing. Recycling phosphorus from excreta or other organic wastes presents an important opportunity to recover phosphate
  • Recycling nitrogen and phosphorus from wastewater systems, in cities, agriculture and industry. This includes treatment of agricultural point sources, where manures may not be fully recycled, but enter into water courses, as well as for industrial effluents, with high losses to the environment. One of the greatest challenges is to implement existing technologies. It is attractive to develop strategies that focus on conserving reactive nitrogen in sewage and treating for use as a fertilizer source.
  • Spatial and temporal optimization of nutrient flows

There is urgent need to develop approaches that optimize the planet’s nutrient cycles while reducing threats to climate, ecosystem services and human health. This “Nutrient nexus” can be addressed through strengthening the mandate of the Global Programme of Action for the protection of the marine environment from Land-Based Activities (GPA) to:

  • Establish a global assessment process for nutrient interactions, with operational indicators
  • Improve NUE and establish internationally agreed targets for improved P & N management
  • Quantify the multiple benefits of meeting the nutrient management targets
  • Develop and implement an approach for monitoring time-bound achievement of these targets

Governments in the United States and Canada are working to create new targets for phosphorus loading in Lake Erie to better address the changing drivers of toxic algal blooms in the lake. Draft numbers for the new targets could be released as early as this fall. UNEP, through the GPA will be looking to benefit from this work and build upon it to assist in developing internationally acceptable targets.

Vincent Sweeney is the Coordinator of the Global Programme of Action for the Protection of the Marine Environment from Land Based Activities (GPA)